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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat sperm galactosyl receptor is a member of the C-type animal lectin family showing preferential binding to N-acetylgalactosamine compared to galactose. Binding is mediated by a Ca(2+)-dependent carbohydrate-recognition domain (CRD) identical to that of the minor variant of rat hepatic lectin receptor 2/3 (RHL-2/3). The molecular organization of the genomic DNA, cDNA, and derived amino acid sequence of rat testis galactosyl receptor have been determined and in vitro fertilization studies were conducted to ascertain its role. We have determined that the rat testis galactosyl receptor gene generates two mRNA species: one species, designated liver-type, is identical to RHL-2/3; the other, designated testis-type, contains one unspliced intron (86 nt) which alters the reading frame and changes the amino acid sequence of the carboxyl terminus. As a result, the CRD (glutamine-proline-aspartic acid/QPD) and flanked Ca(2+)-binding amino acid sequences were not present in the testis-type protein. Northern and Southern blots demonstrated presence of transcripts with unspliced intron in rat sperm but not liver. Similarly, antibody, raised against a synthetic 12-amino acid peptide (p12) encoded by the unspliced intron, recognized in immunoblots a 54 kDa receptor protein in protein extracts from testis but not from liver. Immunofluorescence and immunogold electron microscopy studies demonstrated that both protein species localized on the plasma membrane surface of the head and tail of rat sperm. Furthermore, capacitated rat sperm preincubated with polyclonal antisera to RHL-2/3 or to the CRD of the liver-type galactosyl receptor showed a statistically significant decrease in the in vitro fertilization rate. We conclude that rat sperm galactosyl receptor may play a role in egg binding and that an undetermined molecular mechanism operates to generate two proteins with identical intracellular amino terminal domain but only one of them displays a CRD and associated Ca(2+)-binding sites at the carboxyl terminal extracellular domain.
Mol Reprod Dev 2000 Jul
PMID:Molecular cloning of rat sperm galactosyl receptor, a C-type lectin with in vitro egg binding activity. 1086 8

Lectin is regarded as a potential molecule involved in immune recognition and phagocytosis through opsonization in crustacean. Knowledge on lectin at molecular level would help us to understand its regulation mechanism in crustacean immune system. A novel C-type lectin gene (Fclectin) was cloned from hemocytes of Chinese shrimp Fenneropenaeus chinensis by 3' and 5' rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA consists of 1482 bp with an 861 bp open reading frame, encoding 287 amino acids. The deduced amino acid sequence contains a putative signal peptide of 19 amino acids. It also contains two carbohydrate recognition domains/C-type lectin-like domains (CRD1 and CRD2), which share 78% identity with each other. CRD1 and CRD2 showed 34% and 30% identity with that of mannose-binding lectin from Japanese lamprey (Lethenteron japonicum), respectively. Both CRD1 and CRD2 of Fclectin have 11 amino acids residues, which are relatively invariant in animals' C-type lectin CRDs. Five residues at Ca2+ binding site 1 are conserved in Fclectin. The potential Ca2+/carbohydrate-binding (site 2) motif QPD, E, NP (Gln-Pro-Asp, Glu, Asn-Pro) presented in the two CRDs of Fclectin may support its ability to bind galactose-type sugars. It could be deduced that Fclectin is a member of C-type lectin superfamily. Transcripts of Fclectin were found only in hemocytes by Northern blotting and RNA in situ hybridization. The variation of mRNA transcription level in hemocytes during artificial infection with bacteria and white spot syndrome virus (WSSV) was quantitated by capillary electrophoresis after RT-PCR. An exploration of mRNA expression variation after LPS stimulation was carried out in primarily cultured hemocytes in vitro. Expression profiles of Fclectin gene were greatly modified after bacteria, LPS or WSSV challenge. The above-stated data can provide us clues to understand the probable role of C-type lectin in innate immunity of shrimp and would be helpful to shrimp disease control.
Mol Immunol 2007 Jan
PMID:Molecular cloning, characterization and expression analysis of a putative C-type lectin (Fclectin) gene in Chinese shrimp Fenneropenaeus chinensis. 1653 Feb 68

Lectins are regarded as potential immune recognition proteins. In this study, a novel C-type lectin (Fc-Lec2) was cloned from the hepatopancreas of Chinese shrimp, Fenneropenaeus chinensis. The cDNA of Fc-Lec2 is 1219 bp with an open reading frame (ORF) of 1002 bp that encodes a protein of 333 amino acids. Fc-Lec2 contains a signal peptide and two different carbohydrate recognition domains (CRDs) arranged in tandem. The first CRD contains a QPD (Gln-Pro-Asp) motif that has a predicted binding specificity for galactose and the second CRD contains a EPN (Glu-Pro-Asn) motif for mannose. Fc-Lec2 was constitutively expressed in the hepatopancreas of normal shrimp, and its expression was up-regulated in the hepatopancreas of shrimp challenged with bacteria or viruses. Recombinant mature Fc-Lec2 and its two individual CRDs (CRD1 and 2) did not have hemagglutinating activity against animal red blood cells, but agglutinated some gram-positive and gram-negative bacteria in a calcium-dependent manner. The three recombinant proteins also bound to bacteria in the absence of calcium. Fc-Lec2 seems to have broader specificity and higher affinity for bacteria and polysaccharides (peptidoglycan, lipoteichoic acid and lipopolysaccharide) than each of the two individual CRDs. These data suggest that the two CRDs have synergistic effect, and the intact lectin may be more effective in response to bacterial infection, the Fc-Lec2 performs its pattern recognition function by binding to polysaccharides of pathogen cells.
Mol Immunol 2009 May
PMID:A novel C-type lectin with two CRD domains from Chinese shrimp Fenneropenaeus chinensis functions as a pattern recognition protein. 1932 52

Crustaceans are deficient in an adaptive immune system and depend solely on their innate immunity. One kind of pattern recognition proteins which plays an important role in the shrimp immunity is lectin. A new C-type lectin called FmLC2 was cloned from the stomach of the banana shrimp Fenneropenaeus merguiensis by means of RT-PCR and 5' and 3' rapid amplification of cDNA ends (RACE). Its full-length cDNA contains 1098 bp with a single open reading frame of 738 bp, encoding a peptide of 245 amino acids. The deduced amino acid sequence of FmLC2 consists of a signal peptide of 17 amino acids with a molecular mass of 28,115 Da and an isoelectric point of 6.94. The primary structure of FmLC2 comprises a single carbohydrate recognition domain (CRD) with a QPD (Gln-Pro-Asp) motif and one Ca(2+) binding site. Like other C-type lectins, its CRD structure contains a double-loop characteristic being stabilized by two conserved disulfide linkages. The mRNA expression of FmLC2 was detected specifically in the stomach and gills, less was found in the hepatopancreas. Upon inoculation of shrimp with Vibrio harveyi or white spot syndrome virus (WSSV), the FmLC2 expression either in stomach or gills was higher than in the hepatopancreas. Besides, its expression in these tissues was up-regulated to reach the highest levels at 12 or 18 h for V. harveyi or WSSV stimulation, respectively. RNAi-based silencing of FmLC2 resulted in suppression of its expression, increases in mortality when the shrimp were challenged with V. harveyi or WSSV, and the median lethal time was reduced compared with controls. These results suggest that FmLC2 may serve as receptor molecules which recognize invading bacterial and viral pathogens and thus contribute a role in the shrimp immune response.
Mol Cell Probes 2015 Dec
PMID:Cloning and the mRNA expression of a C-type lectin with one carbohydrate recognition domain from Fenneropenaeus merguiensis in response to pathogenic inoculation. 2640 76

C-type lectins participate in hemocytic encapsulation as pattern recognition receptors; however, the molecular mechanisms underlying their function remain unknown. In this study, we determined that the encapsulation-promoting function of a C-type lectin, IML-10, may be related to its interaction with hemocytes in the agricultural pest Ostrinia furnacalis. IML-10 possesses two carbohydrate-recognition domains (CRDs) containing EPN and QPD motifs with 4 and 6 conserved cysteine residues, respectively. IML-10 was found to mainly be secreted by the fat body into the larval plasma, and its expression was induced by Sephadex A-25 beads. Anti-IML-10 antibodies inhibited encapsulation-promoting function of IML-10 in the larval plasma. The encapsulation rate of Sephadex A-25 beads decreased from approximately 90%-30% when expression of IML-10 in O. furnacalis larvae was inhibited by RNAi. Moreover, the Sephadex bead-encapsulating ability of hemocytes decreased to almost zero in O. furnacalis larvae with IML-10 knocked out by CRISPR/Cas9, with IML-10 expression clearly decreasing compared to that of the control. Similar to the larval plasma, recombinant IML-10 promoted Sephadex bead encapsulation by hemocytes. Immunohistochemistry analysis showed that IML-10 was able to bind to the surface of both granulocytes and plasmatocytes but not to Sephadex beads as foreign objects. Furthermore, recombinant IML-10 promoted hemocyte aggregation but not adhesion. Therefore, we speculate that IML-10 binds to the surface of hemocytes to promote their aggregation and further improve their encapsulation capacity. These results contribute to clarifying the function of insect C-type lectins in encapsulation.
Insect Biochem Mol Biol 2020 03
PMID:The C-type lectin IML-10 promotes hemocytic encapsulation by enhancing aggregation of hemocytes in the Asian corn borer Ostrinia furnacalis. 3192 81

C-type lectins (CTLs) are a superfamily of proteins found in almost all vertebrates and invertebrates. They play an important role in innate immune defences, development and epidermal structure. Here, a CTL with one carbohydrate-recognition domain containing a highly conserved Gln-Pro-Asp (QPD) motif was identified in Tribolium castaneum and given the name TcCTL5. Spatiotemporal analyses showed that Tcctl5 was highly expressed in the late pupa stage and mainly existed in the central nervous system and haemolymph. The transcript level of Tcctl5 was prominently induced after bacterial infection. Recombinant TcCTL5 proteins (rTcCTL5) were found to bind to lipopolysaccharide, peptidoglycan and tested bacteria and induce microbial agglutination in the presence of Ca2+ . Interestingly, when Tcctl5 was knocked down, the transcript level of antimicrobial peptides (AMPs) (attacin1, defensins3, coleoptericin1 and cecropins3) was prominently downregulated after induction with Gram-negative Escherichia coli. More interestingly, Tcctl5 was knocked down, leading to increased mortality and loss of locomotor activity, which exhibited less travel distances among early adults. These results demonstrate that Tcctl5 plays an important role in the innate immune reaction and the movement of T. castaneum. Thus, it may represent an alternative molecular target for pest control and thus reduce the use of pesticides in agricultural production.
Insect Mol Biol 2020 Nov 03
PMID:Functions of a C-type lectin with a single carbohydrate-recognition domain in the innate immunity and movement of the red flour beetle, Tribolium castaneum. 3314 45